Everyone is talking about test driven development (TDD) being so cool and elaborating for both developers and persons responsible for the projects success ( like project managers, project owners, and customers ). But very few projects are using TDD to gain its relieving aspects. How does that go along? Seems many project responsibles are uncertain about the efforts and direct benefits of TDD and step back. This talk is about a transition from a usual project to TDD. Within this talk I will raise some questions to be answered before moving and show the benefits of TDD for each party of the project setup. We will find possible impediments to be faced and will see how to get rid of them.

1. Introducing
test driven development
to your project
Bastian Feder Confoo 2011, Montreal
bastian.feder@liip.ch 10th March 2011

2. Me, myself & I
PHP since 2001
Testing and Quality coach @ Liip Inc.
Opensource addict
PHP manual translations
FluentDOM
phpdox

3. What is TDD?
„TDD is a software
development process which
relies on the repetition of very
short development cycles.“
(wikipedia)

4. Development cycle
Test
Refactor Develop

5. Positive feedback cycle

6. Benefits
Higher productivity
Higher confidence
Adjustable complexity
Modularized & clean source code

7. Benefits (cont.)
Less code
Shorter time to market
Agility
Continuity

8. Drawbacks
TDD difficult if functional tests required
Test are created by developer who does the
implementation
High number of unit tests may lead to false sense
of security
Full management support required

9. Transition

10. What to do
before?

11. Rate your software
Software metrics
Executable line of code (eloc)
Cyclomatic complexity (ccn)
Weighted method count (wmc)
(reverse) Code rank (cr)
…

12. Rate your software (cont.)
Documentation
Api
Tutorials
Wiki
…

13. Meanwhile

14. Meanwhile
Setup standards
Coding guidelines
Definition of done
…

15. Meanwhile (cont.)
Setup and prepare your environment
Test server (CI)
Development machines

16. Meanwhile (cont.)
Introduce & educate
Developers
Project responsibles
Management

17. After that

18. What's next?
Determine hotspots of your software
Highly used classes/methods
Missing abstractions

19. What's next? (cont.)
Eliminate one by one
Refactor to testability
(static, singletons, fixed dependencies)
Small iterations to improve the legacy code

20. Establish

21. Establish
Stick to tests, even when it is hard
Act in increments to adapt your developement
method to your needs
Alter your way of working

22. Establish (cont.)
Talk about the source
Keep persons involved up to date
Constant learning and education

23. Questions

24. Links
Rate it @ http://joind.in/2848
Pdepend website (http://pdepend.org)
http://blog.bastian-feder.de
Working Effectively with Legacy Code
(http://www.amazon.de/Working-Effectively-Legacy-Robert-
Martin/dp/0131177052/ref=wl_it_dp_o?
ie=UTF8&coliid=IA3NS7G5GYIT&colid=VCXWUWFBWD5X)
OO Design Quality Metrics
(http://www.objectmentor.com/publications/oodmetrc.pdf)

25. PHP5.3 Powerworkshop
New features of
PHP5.3
Best Pratices using
OOP
PHPUnit
PHPDocumentor

26. License

This set of slides and the source code included
in the download package is licensed under the
Creative Commons Attribution-Noncommercial-
Share Alike 2.0 Generic License
http://creativecommons.org/licenses/by-nc-sa/2.0/deed.en